list1=[1,2,3,2,6,10,1]

a=list1[0]

for i in list1:
    if i>a:
        a=i
print(a)



list2 = [1,2,3,4,'a',1,'b',21]
sum = 0

for i in list2:
    if isinstance(i,int):
        sum=sum+i
print(sum)




x=6
for i in range(2,x):
    if x % i == 0:
        print("不是素数")
        break
else:
    print("是素数")


x=10
sum=0
for i in range(2,x+1):
    for j in range(2,i):
        if i % j ==0:
            break
    else:
        sum = sum + 1
print(sum)

